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/*
* Copyright (C) 2009, Frederic Weisbecker <fweisbec@gmail.com>
*
* Handle the callchains from the stream in an ad-hoc radix tree and then
* sort them in an rbtree.
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <errno.h>
#include "callchain.h"
static void rb_insert_callchain(struct rb_root *root, struct callchain_node *chain)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
struct callchain_node *rnode;
while (*p) {
parent = *p;
rnode = rb_entry(parent, struct callchain_node, rb_node);
if (rnode->hit < chain->hit)
p = &(*p)->rb_left;
else
p = &(*p)->rb_right;
}
rb_link_node(&chain->rb_node, parent, p);
rb_insert_color(&chain->rb_node, root);
}
/*
* Once we get every callchains from the stream, we can now
* sort them by hit
*/
void sort_chain_to_rbtree(struct rb_root *rb_root, struct callchain_node *node)
{
struct callchain_node *child;
list_for_each_entry(child, &node->children, brothers)
sort_chain_to_rbtree(rb_root, child);
if (node->hit)
rb_insert_callchain(rb_root, node);
}
static struct callchain_node *create_child(struct callchain_node *parent)
{
struct callchain_node *new;
new = malloc(sizeof(*new));
if (!new) {
perror("not enough memory to create child for code path tree");
return NULL;
}
new->parent = parent;
INIT_LIST_HEAD(&new->children);
INIT_LIST_HEAD(&new->val);
list_add_tail(&new->brothers, &parent->children);
return new;
}
static void
fill_node(struct callchain_node *node, struct ip_callchain *chain, int start)
{
int i;
for (i = start; i < chain->nr; i++) {
struct callchain_list *call;
call = malloc(sizeof(*chain));
if (!call) {
perror("not enough memory for the code path tree");
return;
}
call->ip = chain->ips[i];
list_add_tail(&call->list, &node->val);
}
node->val_nr = i - start;
}
static void add_child(struct callchain_node *parent, struct ip_callchain *chain)
{
struct callchain_node *new;
new = create_child(parent);
fill_node(new, chain, parent->val_nr);
new->hit = 1;
}
static void
split_add_child(struct callchain_node *parent, struct ip_callchain *chain,
struct callchain_list *to_split, int idx)
{
struct callchain_node *new;
/* split */
new = create_child(parent);
list_move_tail(&to_split->list, &new->val);
new->hit = parent->hit;
parent->hit = 0;
parent->val_nr = idx;
/* create the new one */
add_child(parent, chain);
}
static int
__append_chain(struct callchain_node *root, struct ip_callchain *chain,
int start);
static int
__append_chain_children(struct callchain_node *root, struct ip_callchain *chain)
{
struct callchain_node *rnode;
/* lookup in childrens */
list_for_each_entry(rnode, &root->children, brothers) {
int ret = __append_chain(rnode, chain, root->val_nr);
if (!ret)
return 0;
}
return -1;
}
static int
__append_chain(struct callchain_node *root, struct ip_callchain *chain,
int start)
{
struct callchain_list *cnode;
int i = start;
bool found = false;
/* lookup in the current node */
list_for_each_entry(cnode, &root->val, list) {
if (cnode->ip != chain->ips[i++])
break;
if (!found)
found = true;
if (i == chain->nr)
break;
}
/* matches not, relay on the parent */
if (!found)
return -1;
/* we match only a part of the node. Split it and add the new chain */
if (i < root->val_nr) {
split_add_child(root, chain, cnode, i);
return 0;
}
/* we match 100% of the path, increment the hit */
if (i == root->val_nr) {
root->hit++;
return 0;
}
return __append_chain_children(root, chain);
}
void append_chain(struct callchain_node *root, struct ip_callchain *chain)
{
if (__append_chain_children(root, chain) == -1)
add_child(root, chain);
}
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